Difference between a 30mm red dot sight and a 40mm red dot sight?

[Chickasaw]

I'm think of putting on of these:

http://www.cabelas.com/cabelas/en/te...-box.jsp.form1

On my AK47. But I'm wondering what the difference is between the 40mm and the 30mm.



thanks

[LifexIsxHunting]

The front objective lens in measured in milimeters (mm). So one is 30 mm and the other is 40mm. The 40mm would be slightly bigger.

[Bernie P.]

Id get the 40mm.Bigger will gather more light all else being equal.

[skb2706]

Exactly 10 mm.

[Pawildman]

Originally Posted by skb2706

Exactly 10 mm.

........ You beat me to it.......

[Knightia]

Exactly 10 mm.

Originally Posted by Pawildman

........ You beat me to it.......

Yep